By Damian McNamara
Miami Beach—Administration of local or regional anesthesia before some major operations can prevent long-term pain for patients at five to six months postoperatively, according to a recent meta-analysis.
“A large percentage of people have pain at six months, especially after thoracotomy, breast cancer surgery and cesarean section,” Michael H. Andreae, MD, said in an interview at the annual Fall Meeting of the American Society of Regional Anesthesia and Pain Medicine.
Dr. Andreae and his associate, Doerthe A. Andreae, MD, identified 23 double-blind, randomized controlled trials in the literature that compared local or regional anesthesia technology (epidural, spinal or local blocks) with conventional treatment of pain (nonsteroidal anti-inflammatory drugs [NSAID] or morphine) and grouped them according to the surgical intervention. Many studies showed that local or regional anesthesia can prevent chronic pain after different surgical interventions, but a meta-analysis could only be performed if there was more than one study in a surgical subgroup.
The researchers found that thoracotomy patients have a lower likelihood of chronic pain at six months if they receive regional anesthesia instead of conventional pain control (odds ratio [OR], 0.33). This result comes from pooled analysis of 250 study participants. “An epidural … prevents pain six months down the road,” said Dr. M. Andreae, of the Department of Anesthesiology at Montefiore Medical Center/Albert Einstein College of Medicine, in New York City. “We were surprised to find the results were so clear; this is important because chronic pain after thoracotomy is so difficult to treat.”
The analysis of 89 patients who underwent surgery for breast cancer found that those who received a paravertebral block were less likely to experience pain five or six months postoperatively (OR, 0.37). Put another way, an epidural for thoracotomy or a paravertebral block for breast cancer surgery can prevent chronic pain in one patient for approximately every four to five patients treated. “Chronic pain can have a tremendous impact on quality of life; this is why prevention is paramount,” said Dr. Andreae. These and other findings were published Oct. 17, 2012, in the Cochrane Database of Systematic Reviews (2012, Issue 10. Art. No.: CD007105. doi: 10.1002/14651858.CD007105.pub2.).
“We as anesthesiologists have to become perioperative physicians and take a role in what happens after surgery,” Dr. Andreae said.
Dr. Andreae also has a message for surgeons. “Chronic pain after surgery is underappreciated by surgeons, but it’s very important to the patient.” Some surgeons don’t realize pain can persist this far into the postoperative period, he added, or that prevention of pain with just a small amount of regional anesthesia can be very effective. “Even use of a single paravertebral block … or a single-shot intervention” can alleviate significant pain.
Simple infiltration of a wound before closure can be beneficial as well. “This doesn’t cost more and doesn’t increase [the rate of] infection,” he added.
Many patients also need education, Dr. Andreae said. “When we tell them about a block, some say ‘just knock me out.’” Some patients may not understand how regional anesthesia works or—as this study points out—how it can be advantageous in the long run, he said.
“Dr. Andreae’s review is extremely important in that it clearly demonstrates that chronic pain is reduced when regional anesthesia and analgesia are used, which is a very important argument for the widespread use of these techniques,” said Arthur Atchabahian, MD, when asked to comment.
“A next step might be to evaluate possible long-term benefits from other modalities of acute postoperative pain control, such as multimodal pharmacologic analgesia,” said Dr. Atchabahian of the Department of Anesthesiology at New York University Langone Medical Center, in New York City. He was not affiliated with the current study.
The dichotomous responder analysis (patients either had pain or did not) made for a very clean study, “but chronic pain is a very complex concept that is not well captured by a yes/no answer,” Dr. Andreae said. Another potential limitation was the intermediate quality of the studies included in the meta-analysis, and the authors cautioned against overinterpretation of findings based on a small number of studies.
The investigators only included studies of adults. In the future, Dr. Andreae would like to assess chronic pain in children after surgery, as well as expand his current findings to another meta-analysis that assesses different types of surgical procedures.